When Grant MH 01206 was initiated nearly sixteen years ago, the primary objectives of our research program were the investigation and analyses of the phenomena of unconscious perception and discrimination and learning without awareness. Experimental pursuit of these phenomena have led to our present concern with basic questions concerning attentional phenomena and coding processes in visual perception. It is the broad aim of our research program at present to understand and describe the underlying processes involved in attentional phenomena particularly as they are manifest in visual perception.